Date: Wed, 11 Aug 2010 18:54:19 -0500 From: Ryan Coleman <ryan.coleman@cwis.biz> To: David Brodbeck <gull@gull.us> Cc: freebsd-questions@freebsd.org Subject: Re: UPS question Message-ID: <C95C5847-BDB2-433A-BF6F-BB8C8AE4E5BF@cwis.biz> In-Reply-To: <cc009d380d95eaa9fee8328a6bbfe4fe.squirrel@www.gull.us> References: <E1B44814-1433-4FBE-902B-BCC1944FBFCD@cwis.biz> <3135A83C-6FD9-4C3B-958F-11EE85221061@mac.com> <5304A319-0406-4510-B6B2-8FD609239FF9@cwis.biz> <43a2b1b16a03a5c58dfb7beaadd0c535.squirrel@www.gull.us> <3AB9F23A-B56C-4176-83C9-F248161066B9@cwis.biz> <cc009d380d95eaa9fee8328a6bbfe4fe.squirrel@www.gull.us>
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On Aug 11, 2010, at 6:01 PM, David Brodbeck wrote: > On Wed, August 11, 2010 1:18 pm, Ryan Coleman wrote: >> On Aug 11, 2010, at 3:06 PM, David Brodbeck wrote: >>=20 >>> On Wed, August 11, 2010 12:25 pm, Ryan Coleman wrote: >>>> He thinks that at 500W needed it would give me about 12 minutes on = a >>>> 1400VA. My consideration is, then, give the server 2 minutes on >>>> battery. >>>> If full power has not been returned, shut down the server but leave = the >>>> modem (w/ wireless) and switch running with power for up to 6 = hours. >>>=20 >>> A bit of advice: If this is an unattended system, give some thought = to >>> how >>> you will boot the server back up if the outage is longer than two >>> minutes >>> but shorter than six hours. Most UPS installations have *some* kind = of >>> race condition issue if power comes back after the servers have = begun a >>> shutdown, but in your case it's an unusually long window. >>=20 >> Meaning that my 2-minute window is unusually long? If the UPS can = support >> the system for 12 minutes, I say give it 20% of the life of the = support >> because our power outages here are usually spikes that kill my = current web >> server (but amazingly *not* my file server). In fact, one of those = power >> fluxes occurred last night. I love storms for the light shows, but = hate >> them for the toll they take on my servers. >=20 > Nope, 2 minutes is fine, maybe even short depending on how long your > system takes to shut down. What I'm asking about is this scenario: >=20 > 1. Power goes out. > 2. Server shuts itself down after 2 minutes. > 3. Power comes back on before the UPS batteries are exhausted. >=20 > The server never sees a power cycle, so it doesn't boot itself back up > until someone physically goes and pushes the button. Good points. I just want to make sure it has a safe shutdown (the usual = reason for a UPS) but it will be set with a BIOS turn on time if it is = not on. This is for a mirrored archive that updates overnight. If it is = in the middle of the process it will kill and shut off. Most power outages in my area are 1) during the hottest days of the = summer - like today and 2) last less than 60 seconds. It's biggest draw = is to give it a steady stream of power. -- Ryan=
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